1. Field of the Invention
The invention relates to an optical sensor. In particular, the invention relates to a reading head utilizing the optical sensor for reading out contents printed on a printed product such as a news paper which is fed in a direction. The invention also relates to a reading head utilizing the optical sensor for reading out contents formed on a printing plate for printing, the printing plate being fed in a direction.
2. Description of Related Art
There has been proposed a reading head for reading out contents printed on a printed product which is fed in a direction, as disclosed in Japanese Laid-Open Patent Publication No. 156,080 of 1997. The reading head includes a circuit board extending in a direction vertical to the feeding direction of the printed product. The reading head further includes a plurality of optical sensors arranged in line longitudinally of the circuit board.
Each of the optical sensors includes LEDs which are fixedly mounted on and electrically connected with the circuit board by soldering to complete a first electronic circuit through the LEDs. The LEDs are energized by the first electronic circuit for directing a light onto the printed product to illuminate the printed product with the light and generate a reflected light reflected from the printed product. Each of the optical sensors further includes photo detecting means comprising a photo diode array which is also fixedly mounted on and electrically connected with the circuit board by soldering to complete a second electronic circuit through the photo detecting means. The photo detecting means is energized by the second electronic circuit for receiving and detecting the reflected light reflected from the printed product to read out the contents printed on the printed product.
By the way, the LEDs or the photo detecting means may be damaged by accident in each of the optical sensors. In the case, the LEDs or the photo detecting means has to be exchanged for new one, otherwise the reading head can not satisfactorily read out the contents printed on the printed product. However, the reading head is problematic in that the LEDs or the photo detecting means is difficult to be exchanged for new one because it is fixedly mounted on the circuit board by soldering. Even if the LEDs or the photo detecting means can be forcibly removed from the circuit board, the new one must then be carefully mounted on the circuit board by soldering to obtain a precision in position and angle of the LEDs and the photo detecting means with respect to the circuit board. In particular, the photo detecting means would receive and detect the reflected light at a light receiving and detecting amount which varies with the angle of the photo detecting means. It is therefore required to make the angle of the photo detecting means in each of the optical sensors to be constant so that the photo detecting means can receive and detect the reflected light without difference in light receiving and detecting amount between the optical sensors to precisely read out the contents printed on the printed product. This involves labour, time, special tools or jigs and skillfulness to be impractical. Accordingly, all the reading head is commonly obliged to be exchanged for new one whenever the LEDs or the photo detecting means is damaged by accident in each of the optical sensors, resulting in expense.
It is therefore an object of the invention to provide a new and improved optical sensor, to overcome the above problems.
Other object of the invention is to provide the optical sensor in which LEDs or photo detecting means can be exchanged for new one without difficulty.
Other object of the invention is to obtain a precision in position and angle of the LEDs and the photo detecting means after exchange.
According to the invention, there is provided an optical sensor comprising a holder provided on a circuit board. The holder has first and second cavity means formed therein.
The optical sensor further comprises first body means including LEDs combined therewith for directing a light onto an object to illuminate the object with the light and generate a reflected light reflected from the object. The first body means is of a cassette type adapted to be fitted into and held in the first cavity means of the holder for removal. The first body means is electrically connected with the circuit board to complete a first electronic circuit through the LEDs when fitted into the first cavity means.
The optical sensor further comprises second body means including photo detecting means combined therewith for receiving and detecting the reflected light reflected from the object. The second body means is of a cassette type adapted to be fitted into and held in the second cavity means of the holder for removal. The second body means is electrically connected with the circuit board to complete a second electronic circuit through the photo detecting means when fitted into the second cavity means.
The object may comprise a printed product including contents printed thereon. The optical sensor may be intended to read out the contents of the printed product.
The object may comprise a printing plate including contents formed thereon for printing. The optical sensor may be intended to read out the contents of the printing plate.
In a preferred embodiment, the first cavity means is formed in the holder to have a depth in a direction toward the circuit board. The second cavity means is also formed in the holder to have a depth in the direction toward the circuit board. The first and second body means are inserted and fitted into the first and second cavity means in the direction toward the circuit board.
In addition, the first and second cavity means are formed in the holder side by side to extend parallel to each other along the circuit board. The first and second body means are held in the first and second cavity means side by side to extend parallel to each other along the circuit board.
The second cavity means comprises two second cavities formed in the holder. The first cavity means comprises a first cavity formed in the holder to be interposed between the second cavities. The second body means comprises two second bodies held in the second cavities. The first body means comprises a first body held in the first cavity to be interposed between the second bodies.
The first body includes a plurality of LEDs combined therewith and arranged in line longitudinally of the first body.
The LEDs comprise white LEDs for directing a white light onto the object to illuminate the object with the white light. The photo detecting means comprises photo transistors for receiving and detecting the reflected light reflected from the object.
The circuit board includes board terminal means formed therein at a position corresponding to the holder. The holder includes a bottom surface opposed to the circuit board and first and second through hole means formed in the bottom surface. The first body means further includes first terminal means and first conductor means combined with the first body means. The first terminal means is electrically connected with the LEDs by the first conductor means in the first body means. The first terminal means is inserted into the first through hole means to pass through the first through hole means when the first body means is fitted into the first cavity means. The second body means further includes second terminal means and second conductor means combined with the second body means. The second terminal means is electrically connected with the photo detecting means by the second conductor means in the second body means. The second terminal means is inserted into the second through hole means to pass through the second through hole means when the second body means is fitted into the second cavity means. The first and second terminal means protrude toward and contact with the board terminal means to complete the first and second electronic circuits respectively.
Furthermore, the first body means comprises split body means made of ultrasonically weldable material and split into two portions along a first split plane extending longitudinally of the first body means and transversely to the circuit board. The portions of the first body means include first recess means formed thereon along the first split plane for accommodating the first terminal means and the first conductor means. The portions of the first body means are ultrasonically welded to each other so that the first terminal means and the first conductor means can be sandwiched between the portions of the first body means to be combined therewith. The LEDs are disposed in position along the first split line and engaged and combined with the first body means to protrude therefrom. The second body means comprises split body means made of ultrasonically weldable material and split into two portions along a second split plane extending longitudinally of the second body means and transversely to the circuit board. The portions of the second body means include second recess means formed thereon along the second split plane for accommodating the photo detecting means, the second terminal means and the second conductor means. The portions of the second body means are ultrasonically welded to each other so that the photo detecting means, the second terminal means and the second conductor means can be sandwiched between the portions of the second body means to be combined therewith.
The LEDs, the first terminal means and the first conductor means may be ultrasonically welded to the first body means to be combined therewith. The photo detecting means, the second terminal means and the second conductor means may also be ultrasonically welded to the second body means to be combined therewith.
The first body means may include at least an electrical connection point formed between the LEDs, the first terminal means and the first conductor means. The second body means may include at least an electrical connection point formed between the photo detecting means, the second terminal means and the second conductor means. The electrical connection points may be ultrasonically welded to be electrically connected in the first and second body means.
An electrically conductive adhesive may be applied onto the electrical connection points in the first and second body means to keep the electrical connection points being electrically connected.
The first body means may further include first resistor means combined therewith. In the embodiment, the first terminal means is electrically connected with the LEDs and the first resistor means by the first conductor means in the first body means to complete the first electronic circuit through the LEDs and the first resistor means. The second body means may further include second resistor means combined therewith. In the embodiment, the second terminal means is electrically connected with the photo detecting means and the second resistor means by the second conductor means in the second body means to complete the second electronic circuit through the photo detecting means and the second resistor means.
In the embodiment, the first recess means is formed on the portions of the first body means along the first split plane for accommodating the first terminal means, the first conductor means and the first resistor means. The portions of the first body means are ultrasonically welded to each other so that the first terminal means, the first conductor means and the first resistor means can be sandwiched between the portions of the first body means to be combined therewith. The second recess means is formed on the portions of the second body means along the second split plane for accommodating the photo detecting means, the second terminal means, the second conductor means and the second resistor means. The portions of the second body means are ultrasonically welded to each other so that the photo detecting means, the second terminal means, the second conductor means and the second resistor means can be sandwiched between the portions of the second body means to be combined therewith.
The first resistor means may be ultrasonically welded to the first body means to be combined therewith. The second resistor means may be ultrasonically welded to the second body means to be combined therewith.
The first body means may include at least an electrical connection point formed between the LEDs, the first terminal means, the first conductor means and the first resistor means. The second body means may include at least an electrical connection point formed between the photo detecting means, the second terminal means, the second conductor means and the second resistor means. The electrical connection points may be ultrasonically welded to be electrically connected in the first and second body means.
An electrically conductive adhesive may be applied onto the electrical connection points in the first and second body means to keep the electrical connection points being electrically connected.
Each of the first and second body means may further include side surface means extending longitudinally of the first and second body means and transversely to the circuit board. The first body means may further include first radiator hole means formed in the side surface means thereof at a position corresponding to the first resistor means for radiating heat caused by the first resistor means. The second body means may further include second radiator hole means formed in the side surface means thereof at a position corresponding to the second resistor means for radiating heat caused by the second resistor means.
The first and second cavity means may be separated by partition means extending therebetween.
In the embodiment, the first body means may include opposite side surfaces extending longitudinally thereof and transversely to the circuit board. The first cavity means may include opposite inner surfaces opposed to the opposite side surfaces of the first body means with clearances formed therebetween. The second body means may include opposite side surfaces extending longitudinally thereof and transversely to the circuit board. The second cavity means may include opposite inner surfaces opposed to the opposite side surfaces of the second body means with clearances formed therebetween.
The clearances may be formed by additional means formed on the opposite inner surfaces of the first and second cavity means. The additional means may comprise elongated raised means formed on the opposite inner surfaces of the first and second cavity means to extend in the direction in which the first and second body means are inserted and fitted into the first and second cavity means.
The clearances may be formed by additional means formed on the opposite side surfaces of the first and second body means. The additional means may comprise elongated raised means formed on the opposite side surfaces of the first and second body means to extend in the direction in which the first and second body means are inserted and fitted into the first and second cavity means.
In other embodiment, one of the side surfaces of the first body means may be opposed to one of the side surfaces of the second body means with a clearance formed therebetween.
The holder may be fixedly mounted on the circuit board. The circuit board may include through hole means formed therein, the holder including pin means adapted to be inserted and fitted into the through hole means of the circuit board for positioning the holder when mounted on the circuit board.
The holder may include reflector surfaces formed thereon, the reflected light being reflected from the object toward the reflector surfaces and then reflected from the reflector surfaces toward the object.
There is also provided a reading head for reading out contents printed on a printed product which is fed in a direction. The reading head comprises the circuit board extending in a direction vertical to the feeding direction of the printed product. The reading head further comprises a linear sensor which comprises a plurality of optical sensors arranged in line longitudinally of the circuit board. Each of the optical sensors comprises the first body means which is of a cassette type adapted to be fitted into and held in the first cavity means of the holder for removal so that the first body means can be exchanged for new one. The optical sensor further comprises second body means which is of a cassette type adapted to be fitted into and held in the second cavity means of the holder for removal so that the second body means can be exchanged for new one.
There is also provided a reading head for reading out contents formed on a printing plate for printing, the printing plate being fed in a direction. The reading head comprises the circuit board extending in a direction vertical to the feeding direction of the printing plate. The reading head further comprises a linear sensor which comprises a plurality of optical sensors arranged in line longitudinally of the circuit board. Each of the optical sensors comprises the first body means which is of a cassette type adapted to be fitted into and held in the first cavity means of the holder for removal so that the first body means can be exchanged for new one. The optical sensor further comprises the second body means which is of a cassette type adapted to be fitted into and held in the second cavity means of the holder for removal so that the second body means can be exchanged for new one.